3 

 2. Lepas fascicularis Ellis & Solander. 



This species which is rather common in tropical seas was observed once only during 

 the cruise of die "Siboga", viz. on Aug. 22, 1899 (Station 165), anchorage on north-east side 

 of Daram Island (False Pisangs), East Coast of Misool. 



There are medium-sized and small specimens ; the larger ones have the capitulum 

 20 mm. long. 



The valves stand at a certain distance from each other and have very distinctly brown- 

 coloured margins. The shape of the carina nearly approaches that of the typical form ; the 

 lower part however does not expand in such a broad disc as figured by Darwin. 



Some of the specimens are attached to fuci associated with young specimens of L. 

 anserifera\ others form a group which is attached to a small brown ball of vegetable origin. 



Genus Poecilasma Darwin 



When proposing the new genus Poecilasma, Darwin (185 i) knew five species belonging 

 to it ; he thought it probable, however, that several more would be discovered later. 



This prediction of Darwin can be said to have been fully realised : I am not quite sure 

 that all descriptions of new forms have become known to me, but certainly eleven new species 

 have come to my notice up to date, viz. : 



Hoek, Cirripedia "Challenger", 1883, 2 species. 



Aurivillius, Studiën über Cirripedien, 1894, 4 species. 



Aurivillius, Cirripèdes "Princesse-Alice", 1898, . . . 1 species. 



Gruvel, Lépadides nouveaux British Museum, 1902, 1 species. 



Hoek, Cirripedia "Siboga", 1907, 3 species. 



Of some of these species it is questionable, whether they are really "good" species: for 

 example, as P. aurantium Darwin is considered by Gruvel l to be a variety of P. Kaempferi\ 

 I think also, that it is doubtful whether P. amygdalum Auriv. and P. lenticula Auriv. are really 

 different from one another and from Darwin's P. fissum. But even then 9 new forms would 

 remain : a not unimportant increase to the number known to Darwin. 



The mutual affinities of the species of Poecilasma are not easily understood. P. Kacmpferi 

 Darwin (with aurantium Darwin), P. dubiuin n. sp., P. carinatum Hoek and P. gracile Hoek 

 seem to form a natural group of true Poecilasmas, mainly differing from one another in the 

 shape and size of the carina. The species with the scutum composed of two segments form a 

 second apparently natural group : they are P. fissum Darwin (with amygdalum Auriv. and 

 lenticula Auriv.), P. cxcavatum n. sp., P. minutum Gruvel, P. tridens Auriv. and P. vagans 

 Aurivillius. Of these species P. cxcavatum n. sp. and P . minutum Gruvel may turn out to be 

 much more nearly related than the others. The remaining species: P. crassum Gray (with 

 P. tinguiculus Auriv.), P . obliquum n. sp. P. eburneum Hinds might be considered to form a 



1 Gruvel, A., Cirripèdes. Expéditions du Travailleur et du Talisman. Paris, 1902. 



3 



